Edit in JSFiddle

var Entry = Marionette.ItemView.extend({
    events: {
        "click .remove": "destroy"
    }
});

$('li').each(function(i,v){
    new Entry({el: v});
});

<h1> The guest book </h1>
<hr>
<ul>
    <li> Tom Jones <span class='remove'>X</span></li>
    <li> Omar Williams <span class='remove'>X</span></li>
    <li> Tina Houstan <span class='remove'>X</span></li>    
</ul>